DOC＋POC发动机燃用不同基准燃油尾气排放研究

摘要

On a State Ⅳdiesel engine with DOC+POC device ,the high sulfur diesel ,State Ⅲ diesel ,State Ⅳ diesel and StateⅤ diesel were tested by the ESC cycle and the CO ,HC ,NOx and PM emission were measured with AVL AMA i60 analyzer . The influences of different standard fuels on diesel engine emission were researched and compared with the original engine .The results show that the conversion rates of CO and HC are well related to sulfur content and DOC + POC device can reduce the CO and HC emission .The average conversion rates of CO and HC for State Ⅴ diesel in ESC cycle are 90 .6% and 86 .6% re-spectively and increase with the decrease of sulfur content ,especially in high speed and high load .Due to the limit of sulfur content ,DOC+POC device cannot reduce the PM emission of high sulfur diesel ,State Ⅲ diesel and State Ⅳ diesel and increase the PM emission contrarily .For State Ⅴ diesel ,DOC+POC device can reduce the PM emission by 81 .8% .%采用高硫柴油、国Ⅲ、国Ⅳ和国Ⅴ4种不同硫含量的基准燃油，在发动机台架上进行了加装DOC＋ POC后处理装置的国Ⅳ柴油机的ESC 13工况测试，并用AVL AMA i60气体分析仪对CO ，HC ，NOx 和PM 排放进行测量。研究了不同基准燃油对加装DOC＋POC后处理装置的国Ⅳ柴油机的排放影响，并与原机作了对比。研究结果表明，CO和 HC的转化效率与燃油硫含量有很好的相关性，DOC＋ POC 后处理可有效减小CO和 HC的排放，稳态循环下国Ⅴ柴油CO和HC的平均转化效率分别为90．6％和86．6％，且随着燃油中含硫量的降低而增大，特别是在高转速大负荷工况。受燃油硫含量影响，DOC＋ POC 后处理装置对高硫柴油、国Ⅲ、国Ⅳ3种燃油的PM排放降低不起作用，反而会使PM 排放增加，然而对国Ⅴ柴油的PM净化率可达81．8％。